For several years, Tampa Bay, Florida residents have been annoyed by a low-frequency thumping noise at night.
"We literally questioned if it was aliens," said Emelle Lee who heard the sound near the ocean. "It was so loud that a few other people came out of their homes to check it out."
While theories abounded—from the acoustic effects of dense fog to neighbors playing bass-heavy EDM—fish acoustician James Locascio of the MOTE Marine Laboratory and Aquarium may have solved the mystery. It's most likely mating calls of black drum fish or the animals actually having sex, he explains.
From Atlas Obscura:
In 2005, as part of his dissertation, Locascio helped communities in Punta Gorda and Cape Coral—about an hour's drive south of Tampa—trace their own mystery noise back to the percussive sound that gives black drum fish their name. The species (Pogonias cromis) makes a bumping-bass beat by flexing muscles against its swim bladder during mass-spawning frenzies.
The loud, low-frequency sound waves can travel long distances, through the ground and potentially into people's homes. Locascio compares it to being disturbed by the thudding of a cranked bass speaker in a passing car when you're tucked in bed. "That's kind of the experience people are having with this."
More wonder in the ocean here.